**Abstract**

The subject of pesticides usage has become a serious threat to sound ecological sustainability. In this regard, the effects of biodegradable multiple pesticides on aquatic biospecies have been discussed in detail. They are always different forms of pesticides in the aquatic environment. These pesticides are bioavailable in both water body and sediments, and the aquatic species do feed on water and sediment materials. The pesticides are also capable to bioaccumulate and biomagnify along the food chain. These attributes pose serious risks to human health and the sound ecological system that is needed for life sustainability. Cancer, infertility, lesions, headache, dizziness, eye irritation, vomiting, dermal diseases, and gastrointestinal problems have been observed as the direct pesticides effects on biological populations in several countries. The needs for different safety guidelines required for pesticides manufacturing and usage have been recommended.

**Keywords:** pesticide, biodegradability, bioaccumulate, biomagnify, water, sediments, aquatic biospecies

## **1. Introduction**

Aquatic ecosystems are complex systems that are the compass of nutrients, biotic pelagic and benthic communities, pools of detritus and that have the bulk of both water and sediment [1, 2]. Anthropogenic activities lead to multiple types of stresses, including emissions of pesticides and nutrients into the environment [3, 4]. These pesticides are capable of affecting species in the aquatic ecosystems and the nutrients can cause eutrophication. Emissions of pesticides can also lead to accumulation in the environmental compartments of water and the complex matrix that forms the sediment. Simultaneous pesticides bioaccumulation into organic substances such as biota and detritus prove to have an adverse effect on aquatic bio-species. Various toxicokinetic models have described these types of accumulations [5].

#### **1.1 Environmental pollution**

Recently, the cry for environmental pesticides pollution is heard from every nook and crannies of the world. Pollution of pesticides has now become a distinct threat to the very existence of mankind and animals on this earth. It is a problem challenge for our days. In the past, man has been disturbing the balance of nature for comfort, wealth, and ego, but now nature has started disturbing the balance of nature. In the late century, there has been growing concern in developing countries and developed countries over the pollution effects from sources, such as sewage, pesticides, and trade effluents discharged from domestic habitations and by the industrial units [6].

The immediate catastrophic effects of pesticides pollution by some industrial units and agricultural application of pesticides have pointed out the essence of its environmental effects: prevention and control. There is now a global awareness that pesticides production and utilization activities in the future time need to be assessed for their environmental hazard or effects without any form of compromise to the said assessment. Too much rise in pesticides application and their industrial production activities in the past have led to the emission of harmful pesticides into human and aquatic habitats and have led to various ecological issues.

Disturbance of pesticides emission has become a serious threat to both human and animals life and it puts the ecosystem out of balance. Maintenance of ecological balance and environmental purity due to the sudden increase in the production of pesticides and their applications in both the home and agricultural sector should be the inclusive concern of each member of society. This situation could be improved through awareness program creation, which must gain the support of people from all works of life with the aim of enlighten them on its pros and cons and their responsibilities that will meet up with the global standard. Pesticides pollution under discussion here has a different meaning and environmental disorder to different biological organisms. Human beings feed on aquatic animals, fishes and drink untreated water. Thus, they are more susceptible to multiple pesticides effects than aquatic animals that feed on prey and uptake water only. This discussion cannot exclude how water is important to all living organisms as it sustains life as the human body depends on water for about seventy percent (70%) to function normally.

Yichen et al. [5] also pointed out the indisputable dependability of water by living organisms as it functions in every living organism cell and cell is said to be the smallest unit of life. In order to reduce and prevent the issues of pesticides pollution in an aquatic habitat, law enforcement agencies have primary responsibilities of ensuring that laws and implantation of pesticides used must be seriously put in place. Companies or industries operating along rivers, seas, and lakes banks, to mention a few, need to redirect their discharge wastes formally channeled into water bodies to a sustainable environment (**Figure 1**) [7].

#### **1.2 Pesticides and environmental pollution**

Pesticides pollution have different routes into aquatic organism domesticated habitat such as leaching from the agricultural farm, erosion from farmlands during

**Figure 1.** *Environmental pollution.*

#### *Effect of Biodegradable Multiple Pesticides on Aquatic Biospecies DOI: http://dx.doi.org/10.5772/intechopen.104626*

rainfall, and become available in the water body through spills from industrial effluents and discharges of environmental wastes into water bodies [8]. Pesticides have different meanings to different people. Generally, pesticides are large classification or group of chemical substances that are developed to model and thereafter substitute for a unique molecule in a particular biological process. This implies that the mode of action of pesticides is peculiar to specific organism, plant, or grass such as pests, weeds to mention a few [9].

The issue of poor quality of water is of the utmost environmental problem in the human health-related issues [10]. Pollution from pesticides has contributed to the said threat and it will continue to gain more ground in as much as they are present in water bodies. The primary aim of pesticides production is mostly for specific targeted organisms or plants but their effects are non-targeted as it affects humans, animals, and plants and produces range of toxicity effects which include carcinogenicity [11] and have the ability to disrupt endocrine [12].

The wide usage of pesticides are detected across different nations such as Europe's freshwater. In Ireland, pesticides are present beyond the European Union (EU) permission limit bound on different numbers of inspections [8, 13]. In Europe, freshwaters in the UK were found to be susceptible to pesticide pollution and in Germany, groundwater and sediment materials were specifically polluted due to pesticides applications and discharge [14].

EC legislators have provided different legislation or laws in place to prevent or minimize the discharge of pesticides and their applications in their environment. The legislation includes Water Framework Directive [15], the strategy for the prevention of endocrine-disrupting compounds [16], and the Stockholm convention [17]."

The normal water purification tools or equipment have proved inefficient to remove toxic pesticides substances from water bodies [16]. The need to have an efficient method is of utmost importance to be researched. Up to now, the best efficient pesticides removal methods include photocatalysis and adsorption [18, 19].

Human activities like land cover change, urbanization and industrialization have impaired ecosystems for several decades in order to increase the access to natural resources for an exponentially growing population [20, 21]. The activities of humans have led to the impairment of the planet earth's boundaries and are causing biodiversity loss and climate changes [22, 23]. Keeping the account of human activities on the global freshwater, land use, acidification of oceans, rivers, lakes, and streams are already tending to a threshold value [22]. Rockström et al. [22] in their study have noted that the human population is facing un-quantifiable threats due to freshwater contamination by different forms of contaminants that are unknown in an aquatic environment.

More than 14 million different chemical compounds exist, out of which above 100,000 synthetic chemical compounds are frequently used in consumer products in different countries of the world for different purposes [24, 25]. Thus, an uncertain number of chemicals may potentially be released into the aquatic environment by diverse routes like point sources, remobilization from contaminated sediments, and groundwater input (**Figure 2**) [26].

#### *1.2.1 Routes of pesticides into aquatic environment*

A lot of literature has identified different routes of pesticides to the aquatic environment [27, 28]. It was observed mainly that the rate at which pesticides enter the aquatic environment is not the same with all pesticides. The routes mainly depend on the physiochemical properties, that is, the ability of pesticides to persist for several years or a decade in an environment without totally losing their

concentrations. The land use and climate changes facilitate pesticides entering into an aquatic environment where it was not originally applied. Majorly, pesticides enter into aquatic environment through wind drift during pesticides applications, erosion due to rainfall immediately after pesticides applications to agricultural farmland, migration of living organisms that were affected by the pesticides concentration into the aquatic environment, and through drainage to mention a few.

### **1.3 Mixture of pesticides effect**

In an aquatic environment, different contaminants especially pesticides pollution have been found with different names and concentrations. These pesticides have been found to integrate with each other and form different pesticides with different concentration levels in aquatic habitat [29].

In this century, many agricultural investors (e.g., farmers) have priority for growing high-yielding species of different crops to meet the increasing population demand for food. However, one of the essential phenomena of this subject of discussion is that varieties are that most of those crops are highly prone to different diseases and pests [30], which was evidence to cause about 40–50% of crop loss [31]. As a result of this information, the use of pesticides to protect crops from those pests and diseases, and reduce crop lost, herewith improving the yield quality as well as quantity became necessary [32–34]. In Bangladesh, pesticides were introduced in 1951 but their uses were negligible until the end of the 1960s [35]. An exponential increase in their uses have occurred from 7350 metric tons of active ingredient of pesticides in 1992 to about 45,172 metric tons in 2010 [34].

One of the major reasons for the high rate of pesticides application in some countries such as Bangladesh is due to the adoption of the government policy to increase the control of pests and diseases of crops through a chemical measure process in order to increase overall crop yield and to prevent and control crops losses [34].

More so, about eighty-four (84%) of pesticides significant materials are in the family of 242 trade names of a different group of chemicals namely: organochlorine compound, carbamates, organophosphate, neonicotinoids, pyrethroids, nitro compound, heterocyclic pesticides that are registered in Bangladesh and other parts of

### *Effect of Biodegradable Multiple Pesticides on Aquatic Biospecies DOI: http://dx.doi.org/10.5772/intechopen.104626*

the world and are used in the agricultural sector and household applications [35]. However, organochlorine pesticides have been banned in Bangladesh in 1993 [36] and in many countries of the world because of the nature of their toxicities in both human and aquatic environments and they are capable to bioaccumulate and biomagnify in the biological process of feeding such as food chain [37, 38]. Considering other group of pesticides available, the organophosphorus pesticide has gained popularity in the application by farmers in Bangladesh. In addition, more than 35% of their farmers use organophosphorus pesticide to treat varieties of crops for protection reasons [39]."

Pesticides applied on agricultural land have the capability to reach the aquatic environment through several ways which may include but are not limited to leaching of groundwater, spray drift, runoff of surface water, disposal of pesticides containers nearby or inside rivers, cleaning of pesticides equipment in rivers or lakes [40–42]. The indiscriminate use of pesticides and their disposal methods constitute a major threat to the aquatic organism and have led to eco-toxicological risk. More than sixty percent (60%) of animal protein emanated from fish [43]. Since fish serves as the major source of protein in man's food, the indiscriminate use of pesticides in an aquatic environment needs to be reviewed as their toxic effects on fishes are harmful to their normal behavior, physiology and sometimes lead to their deaths [30, 44–54].

Different studies [55, 56] have shown the adverse effects of pesticides on fish species which include but not limited to histopathological alterations such as kidney, gonad, liver, and gill tissue. A study by Dutta and Maxwell (2003) reported that bluegill fish shows histopathological alteration in the ovary namely; cytoplasmic reaction, cytoplasm, and karyoplasmic clumping, necrosis, and thinning of follicular lining exposed to diazinon, atretic oocytes, and adhesion (**Figure 3**).

**Figure 3.** *Mixtures of pesticides.*

## **1.4 Effect of pesticides on aquatic organisms**

Manufacturers of pesticides especially those that are licensed by the legislators of their respective countries always ensure their products to be selective and specific to targeted organisms in terms of their toxicity effects. Yet, some of them are totally specific, a few of them are relatively specific while the majority of them are not due to their biodegradable process. Pesticides toxicity most times always depends on the mode of applications. Pesticides applied during wind action and those applied closely to rainfall time always drift from the specific area of application to the non-targeted area. Biodegradation and degradation of pesticides vary from one pesticides compound to another. This is always due to their respective elements that are made up of a particular chemical organic compound. Some are more toxic than their original parent compounds while others are less toxic during the splitting of the individual elements that are made up of the compounds [57].

The susceptibility of humans and animals to pesticides mixtures always produces toxicological interactions effects [58]. Exposure effects of multiple pesticides may be toxic or less toxic or have the same effects with exposure to their individual component. Most times, it is more poisonous to be susceptible to pesticides mixture than exposure to their respective individual element at different time period due to their effect of synergy [58].

Some of the related terminologies used for explaining toxicological interactions of exposure to multiple pesticides include but are not limited to:


The effects of exposure to the interactions of pesticides depend on the quality of their application and the prediction of their effects requires enough information regarding the factors responsible for pesticides exposures such as magnitude, time, and toxicity to mention a few.

Antagonism process of pesticides interaction includes functional, chemical, dispositional, and receptor. Functional antagonism occurs when two pesticides counterbalance one another by opposite effects on the same physiological function. Chemical antagonism is a chemical reaction between two pesticides to produce a less toxic product [59].

Pesticides enter into the aquatic environment through different routes such as direct application of pesticides to rivers, seas, lakes, or any other water source to prevent or control weeds, pests, or diseases of crops [59]. Atmospheric nature may truly take place due to the movement of the spray of pesticides from crops surfaces or soil surfaces to the aquatic environment. Yeo et al. [60] noted from their work

*Effect of Biodegradable Multiple Pesticides on Aquatic Biospecies DOI: http://dx.doi.org/10.5772/intechopen.104626*

**Figure 4.** *Effect of pesticides on aquatic organisms.*

the effects of atmospheric concentration of pesticides compounds such as organochlorine pesticides which include: Dichlorodiphenyltrichloroethane (DDTs), heptachlor, endosulfan, chlordane, hexachlorocyclohexanes have reported to have minimum and maximum seasonal variation in a rural setting [61]. Furthermore, plantations have been shown to help in reducing surface soil erosion and influence pesticides biodegradation over time, and could lead to the concentration of pesticides in water [62] (**Figure 4**).

## *1.4.1 Volatilization*

Pesticides have the potential to change their state from one form of state of matter into another [63]. The process of the term pesticide volatilization is motivated and catalyzed by pesticides transportation such as soil, water, plant, and surface matrix sorption [64], transportation by air, and diffusion through the boundary layer. The following factors are said to influence the volatilization of pesticides which include physicochemical properties of pesticides [65] including vapor pressure, water solubility, Henry's law constant, adsorption properties, and some environmental factors including soil moisture and soil/air temperature.

#### *1.4.2 Photolysis*

Photolysis of pesticides occurs whenever pesticide compounds have adequate energy from light and causes decomposition of the compound molecules through either direct or indirect process [66].

Photolysis is also known to involve in some form of organic pesticides compounds reaction such as carbon bond, isomerization, decarboxylation, and ester cleavage [67]. Different type of photolysis rate of reaction always depends on the absorption spectrum of the pesticides involved (Dureja, 2012; [68]). Direct photolysis is said to take place when pesticide absorbs directly from light energy and result in some form of chemical reaction [69].

Pesticides mixture toxicity is always difficult or complex to predict their toxic effects. Various models that are used to predict a toxic mixture of pesticides effects are always based on their structures activity composition and are always formulated for the complex organic compound of heavy pesticides.

However, different pesticides mixtures are expected to change the behavior of biological species from their combined effects than those effects from the concentration of a single compound.

A lot of studies have been carried out on the pesticides effects in relation to different ecological settings which mainly focused on the restricted compound known as organochlorines [70–72]. This said organic compound is capable of assimilating into crops, animals, and entire ecosystem at high rates of pesticides concentration emission [73–74].

#### *1.4.3 Degradation of pesticides*

Several researchers were able to point out that "the degradation of pesticides rates are faster and higher under hot weather. In addition, pesticides solubility is temperature-dependent, that is, the higher the temperature the more soluble it becomes and light intensity was also found to be responsible for the high rate of pesticides degradation [75]." More so, hydrolysis has been found as one of the factors that are responsible for the speedy degradation of pesticides especially when combined with changes in pH and aerobic/anaerobic conditions. The transformation process is mediated by living organisms such as plants, algae, bacteria, or fungi as a result of biodegradation. Complex pesticides like carbon compounds such as synthetic pesticides are used for crops growth as the nutrient substrate is capable of degrading into other compounds or elements [76–78].

Degradation process of the majority of pesticides is mostly affected by bacteria and fungi such as DDT pesticide, chlophyrifos, and cypermethrin. Some factors such as plants, animals (e.g., earthworms), soil moisture, temperature, pH, soil organic matter, carbon source concentration of pesticides greatly influence microbial degradation of pesticides [79–85]. On the whole, most of the microbial activities are found during warm temperatures and in moist soil [9].

During the application of pesticides to a specific area of concern, for instance, crops farm, such pesticides concentration may be watered down by irrigation, runoff water, leaching, rainfall, drainage to the non-targeted environment like groundwater usually pollute aquatic habitant. In addition, pesticides present in the atmosphere, water, soil, or sediment can be degraded via photolysis, hydrolysis, microbial degradation, and biotic uptake [9].

Few workers of the Environmental Protection Agency (EPA) have researched on the possible effects of combined pesticides on aquatic biological species, most especially fish. They reported from their studies that the combined effects of pesticides are often determined as a simulation of their separate effects. Their findings may

*Effect of Biodegradable Multiple Pesticides on Aquatic Biospecies DOI: http://dx.doi.org/10.5772/intechopen.104626*

**Figure 5.** *Degradation of pesticides.*

not mirror the combined effects of pesticides as one may expect because pesticides exist in synergistic form. After their finding, much work has been published in respect of the toxicity effects of combined pesticides effects on fishes and other aquatic organisms. They later found out that accurate and comprehensive data are required to model the effects of pesticides mixture on aquatic and any other living organisms' population.

The toxicity of pesticides on aquatic organisms can be measured in a number of ways. The World Health Organisation [86] measures the toxicity of pesticides under the following headings.


The World Health Organisation only reports the toxicity of individual pesticides in their study on the effects of pesticides on the targeted organism [86]. Most of the harmful pesticides such as LC50, LD50, and the physiochemical pesticides properties were considered (**Figure 5**).
